ICT KTN – Stuart Revell

Wireless Technology & Spectrum

challenges and opportunities

Working group 2012 priorities • Spectrum usage: Wireless WAN & LAN below 6GHz Key technologies

Efficiency and best use, taking into account: Energy, Size, Cost and Spectral

efficiency

How to control and manage usage (inc. interference and coexistence).

Cost and economies of scale – how to leverage at continent level (Europe minimum).

• Mapping technology capability, co-existence, interference

issues and timescale.

<1GHz innovation, DTG LTE test bed, deployment, interference and co-

existence challenges

RF Front End Technology challenge. Including new materials.

Future spectrum release. Issues arising from the release of new

spectrum supporting the 500MHz of Spectrum by 2020 initiative.

Spectrum sharing, management and trading. Technology and

deployment challenges, secondary use / dual use of spectrum inc white

Space, cognitive radio, spectrum management and trading.

https://ktn.innovateuk.org/web/spectrum

Presentation themes • Importance of radio link quality

• Picking the right trade offs

• Challenge, the landscape is changing, we need radical

new ideas, approaches, materials or do we carry on with

conventional radio evolution?

Material used • Wireless Technology & Spectrum group papers developed

by industry.

Digital Dividend – a great example to use and learn from

Radio Technology challenges

Papers available, join for free

https://ktn.innovateuk.org/web/spectrum

Three reports -> Innovation test bed

June 2010 May 2011 August 2011

% of Population penetration 'v' Area (Sq kms) of UK

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Pen

etra

tio

n o

f Po

pu

lati

on

- 5

9.2

M p

eop

le

Area - % of total 242,514 km²

60% of population in approx 10% of land area

High Density 40% of population in approx 3.5% of land area

Very High Density : High 20% of population in approx 1% of land area

Link budget scenarios

Coverage

improvement

example using

enhanced UE

antennas

2 GHz indoor dongle 800 MHz indoor dongle

800 MHz indoor smart antenna 800 MHz external antenna (5 m)

7.2 Mbps 14.4 Mbps 32.4Mbps

Typical coverage

to indoor dongles

Source: Ofcom 'Sitefinder' Mobile Phone Base Station Database http://www.sitefinder.ofcom.org.uk/

800MHz Co-existence and

interference challenges Existing services:

1. Broadcast Television – Digital TV (470-862MHz, Ch60)

2. Communal Antenna Systems (distribution of terrestrial broadcast to multiple

dwellings)

3. Cable Television and home media consumer platforms 15-862MHz

4. Short Range Devices (Adjacent band 863-870MHz, e.g. social alarms)

5. PMSE applications (e.g. wireless microphones, in-ear monitors)

The challenges and opportunities this represents, provides the UK with some

significant opportunities for our R&D community to address locally and benefit

through global exploitation.

LTE-800 Base station (BS)

interference to DTT CH60

Geometry of base station

to TV radio link.

Source: Ofcom Technical

workshop 5/7/11

LTE base station OOB causing

interference to DTT CH60

Geometry of base station

to TV radio link.

Source: Ofcom Technical

workshop 5/7/11

Communal aerials

Geometry of base station

to TV radio link.

Source: Ofcom Technical

workshop 5/7/11

Satellite

DTT

Ch 60 UK TV

Frequency Map

Source :

http://www.ukfree.tv/mapsofsignal.php?c=60&a=1

Single TX coverage area indicated in

green

800MHz Spectrum plan

Co-channel interference between

adjacent areas

Potential impact of DTT on LTE

The emergent DTT clearance plan proposes that DTT clearance programme will

take place on a site by site basis through 2013

1) Co-channel interference from the remaining high power DTT services into any LTE services

operating in adjacent regions

2) Co-channel interference from any LTE deployment affecting the reception of DTT services

in the remaining pre clearance areas

Field strength key

Do you ever watch TV at home and

go on the internet at the same time?

Nielsen:

40 Percent of People Use Smartphones, Tablets While Watching TV

Source: http://www.pcmag.com/article2/0,2817,2394619,00.asp

LTE handset (UE) interference to

DTT CH57-60

72MHz offset from the wanted DTT channel can produce picture break up.

TV and Cable

800MHz Spectrum plan

800MHz Interference and co-existence

challenges: Innovation priorities proposal

Spectrum users

Potential Interferers

Cellular (791-862MHz) Short Range Devices

(863-870MHz)

White Space

(470-

790MHz)

Serv

ices i

mp

acte

d

Cable

(15-862MHz)

Yes – potential co-channel and on

channel breakthrough into CPE No interference

Yes – White Space devices in

close proximity to Home STB

Cellular (791-862MHz)

Yes – potential adjacent

channel interference and

blocking

Yes - potential issue around

790MHz adjacent channel

Digital TV

(470-

790MHz)

Conventional

Systems

Yes – Adjacent channel ch60 and

image channels +9. Potential

interference up to 100MHz away from

Tx channel.

No interference Yes – Geo-location and sensing

to control access

Digital TV

(470-

790MHz)

Communal Antennas

Yes – same as conventional with

potential increase dues to higher

amplification stages and antenna gain /

height.

No interference

Yes – Geo-location and sensing

to control access . Could be

worse…. Need to take account

analogue distribution systems

Short Range Devices

(863-870MHz)

Yes - Potential adjacent channel

interference and blocking No interference

PMSE

(470-

790MHz)

Yes - Potential adjacent channel

interference and blocking No interference

Yes – Geo-location and sensing

to control access

Wireless TIC LTE Test bed

Wireless TIC DTT / SAT Feed

Victims

STB / DTT /

CABLE / SRD

Test chamber

LTE Base

station

LTE Mobile

Innovation opportunities

• Victim solutions

• Transmitted signal (Mobile & BS)

• Terminal radiation

• Signal loading innovation –

establish worse case LTE signals

to avoid

LTE

signals

Test models or

real signals?

Test &

Measurement

Test and measurement

• Mobile test model

• BS test model

• Industry standard models

Wireless TIC

Facilities – Vauxhall, London

GTEM Cell in basement Zoo – multiple kit feeds

Signals can be patched between the two

DTG LTE Test bed – Innovation opportunities

Short term

• Base station

Transmitter mask / filters / OOB

Antenna

Radio planning

• UE and Base station - L2 MAC and scheduling

• Radio planning: co-operative, cellular and broadcast

• Home / CPE

Antennae

Amplifiers

Filters

Cables

Connectors

Longer term

• Collaborative CPE

• Collaborative networks

• Shared infrastructure

• White Space innovation

• New spectrum allocation… 700MHz

Pathloss [dB] = 10 n log10 (distance) + C

n=3.5 (typical value)

Distance 10(L/35)

Radio performance is important:

1dB loss = 14% more sites

Source: ICT KTN and Cambridge Wireless RF Front-End Technology Challenges Paper, Sep ‘12

Radio performance is important:

Source: ICT KTN and Cambridge Wireless RF Front-End Technology Challenges Paper, Sep ‘12

Multiple Radio & Modem Technologies

Applications

Processor

Power

Management

Keyboard Audio & Display

Control

Processing

Smart-phone system

Radio: Multiple Bands / Multiple Air Interfaces

WLAN

GPS

2G 3G / HSPA LTE

Bluetooth

Memory / storage Radio modem

MAC (L2) & PHY (L1)

DAB White Space

LTE - A

Source: ICT KTN and Cambridge Wireless RF Front-End Technology Challenges Paper, Oct ‘12

Current Radio Design

Source: ICT KTN and Cambridge Wireless RF Front-End Technology Challenges Paper, Sep ‘12

Technology Throughput RF

bandwidth

Freq

Re-use

Efficiency

bps/MHz

GPRS* 115 kbps 200 kHz 12 48 k

EDGE* 240 kbps 200 kHz 12 100 k

UMTS R99* 750 kbps 5 MHz 1 150 k

HSDPA** 1.7 Mbps 5 MHz 1 340 k

HSPA+ ** 4.2 Mbps 5 MHz 1 840 k

WiMAX** 11.3 Mbps 10 MHz 1 1.13M

LTE** 15 Mbps 10 MHz 1 1.5 M

Notes : *Qualcomm [1] **Vodafone [2]

Note that the assumed efficiency figures are typical and likely to

depend on traffic being uniformly distributed around the cell.

[1] “HSDPA for Improved Downlink Data Transfer”, white paper, 2004 [2] “Broadband through Wireless – the unfolding story of the mobile

web”, presentation by Prof. Michael Walker OBE FREng to Silicon

South West Wireless 2.0 Conference, 2009

Comparison of Spectral efficiency

Comparison of downlink throughput and spectrum

efficiency for various mobile data technologies

Source:

DCKTN Paper - Optimising Mobile Spectrum

Graphical representation of 3GPP defined bands

Source: ICT KTN and Cambridge Wireless RF Front-End Technology Challenges Paper, Sep ‘12

EU-Band Radio LTE Radio

Source: ICT KTN and Cambridge Wireless RF Front-End Technology Challenges Paper, Sep ‘12

LTE Advanced

Figure illustrates the issues that will need to be addressed

in future handset front end targeting LTE-Advanced.

Suggestions for research:

• Conventional approach: Radio design require high performance diplexers

(duplex filters) to ensure that the receiver is not desensitised by the

transmitter. The filters also help to protect adjacent services from transmitter

sidebands and protect the receiver from overload by strong signals which

are part of an adjacent service. Every new band added to a terminal needs

a new filter. SAW or FBAR filters are very small and cheap (~ $1) but each

new band needs another filter and switch, adding cost and losses and

taking more space.

• Can a technology be found that can create tuneable RF filters with lower

cost, reduced losses and greater flexibility?

• Is there any technology or physical phenomenon that might be used to

create a high Q tuneable resonator which could be a building block of such

a filter? Are there innovative hybrid solutions based on a combination of

very high Q fixed resonators with lower Q variable reactance elements that

can help to simplify the design of multi-band radios ? Is it feasible to

eliminate the diplexer and find new ways to achieve simultaneous transmit

and receive?

Source: ICT KTN and Cambridge Wireless RF Front-End Technology Challenges Paper, Sep ‘12

Suggestions for research: • Carbon nano-tubes have been used to make high Q resonators and switching

devices . Is there any way these functions can be combined to make a

tuneable resonator?

• Are there ways of reducing loss and increasing isolation in multi-way RF

switches?

• Are there innovative solutions to both improve the bandwidth and linearity

and reduce unwanted out-of-band radiation by transmitters (PA / driver) or to

improve the strong signal handling of receivers (LNA / mixer)? Such solutions

may be purely in the analogue domain or (more likely) may exploit DSP to

correct for analogue imperfections. Can these improvements be achieved

while continuing to reduce power consumption?

• Are there new digital signal processing techniques that can be used to

linearise or correct for distortions in the analogue domain and consequently

reduce the need for analogue filtering?

• Solutions that span the entire processing chain between the antenna and

baseband digital processing. Set up multi-disciplinary programmes, to bridge

the gap to find the best overall system solutions.

Source: ICT KTN and Cambridge Wireless RF Front-End Technology Challenges Paper, Sep ‘12